Quote Originally Posted by vt_maverick View Post
So how is Marvel different from Seafoam? I seem to remember a recommendation from someone (or maybe it's even on the Seamfoam package) to only add the detergent in the last X many miles before an oil change. Agree that you're cleaning the gunk if you put it in at the oil change, but where is that gunk going over the 3-5K miles between changes? Is it just clogging your oil filter that much faster?
If I recall you add the seafoam before an oil change because it slowly deteriorates your oils ability to lubricate parts. It helps lossen up deposits that would otherwise not move between your 3-5k mile oil change.